RCA BA-6A from scratch
- Thread starter DaveP
- Start date
Help Support GroupDIY Audio Forum:
BA-6A Chassis pics,
I've now finished most of the hard metal bashing (you see, you never know when what you learned at school will come in handy).
The layout is now settled, the amp will be symmetrical, pretty much copying the schematic, only the tubes and output TX will be mounted on the top, all the rest fits inside.
The front panel will be fixed to the rear after the components are all wired up.
There is a removeable rear access panel for the components on the front panel.
The power supply will be in the right hand compartment, with a heavy bussbar passing through the division to the amp. The mains input socket will be the star ground point.
By next week the chassis will be completely finished and the main components will be in place.
best
DaveP
I've now finished most of the hard metal bashing (you see, you never know when what you learned at school will come in handy).
The layout is now settled, the amp will be symmetrical, pretty much copying the schematic, only the tubes and output TX will be mounted on the top, all the rest fits inside.
The front panel will be fixed to the rear after the components are all wired up.
There is a removeable rear access panel for the components on the front panel.
The power supply will be in the right hand compartment, with a heavy bussbar passing through the division to the amp. The mains input socket will be the star ground point.
By next week the chassis will be completely finished and the main components will be in place.
best
DaveP
skal1
Well-known member
Very nice dave p , while your at it build me a case and send it to me ;D
skal1
skal1
Wow this is looking really good i built myself a BA6A fro scratch a few years ago best thing I ever did no other compressor touches it for my vocals no way..... I enjoyed making it too mine not as well made as this brilliant....mine is constantly updated with parts and add ons, I was shopping for a multi turn 10K pot for the balance B, I currently have a single turn and it gets scratchy...when I came across these....
http://cgi.ebay.co.uk/25K-stereo-24-steps-potentiometer-ladder-volume-control-/130430034370?pt=LH_DefaultDomain_0&hash=item1e5e3c61c2#ht_1604wt_698
anyway best of luck...
http://cgi.ebay.co.uk/25K-stereo-24-steps-potentiometer-ladder-volume-control-/130430034370?pt=LH_DefaultDomain_0&hash=item1e5e3c61c2#ht_1604wt_698
anyway best of luck...
Yeah thanks guys, yeah I got the pot now.....what I meant was I was looking for the pot when I came across the daul ladder what I thought could be used for the input of the BA6 ....sorry for the confusion but also thanks....
All the major components now in place.
I attached all the wires before I fitted the parts and noted the colour code, makes it easier than trying to solder in a confined space.
The 7 octal sockets were really fiddly to fit, it took an hour!
After much pondering I fitted the interstage at the front of the amp, that way it makes a compact symmetrical layout with all the wires the same length.
The big earth busbar is in place supported by the shell grounding pin #1's on the octal sockets
The top is quite clean, only the Edcor and the tubes.
Now at last the wiring up starts with resistors and caps going point to point using just the tags.
More next week.....
Best
DaveP
I attached all the wires before I fitted the parts and noted the colour code, makes it easier than trying to solder in a confined space.
The 7 octal sockets were really fiddly to fit, it took an hour!
After much pondering I fitted the interstage at the front of the amp, that way it makes a compact symmetrical layout with all the wires the same length.
The big earth busbar is in place supported by the shell grounding pin #1's on the octal sockets
The top is quite clean, only the Edcor and the tubes.
Now at last the wiring up starts with resistors and caps going point to point using just the tags.
More next week.....
Best
DaveP
Hi Joechris,
There are still a few more parts to go in the spaces left, I just needed to get a few things wired first. I plan to post another photo tomorrow.
It may look easy but it ain't! Hopefully it will be easier for anyone who copies the project, assuming the layout is noise and bug free, that is.
best
DaveP
There are still a few more parts to go in the spaces left, I just needed to get a few things wired first. I plan to post another photo tomorrow.
It may look easy but it ain't! Hopefully it will be easier for anyone who copies the project, assuming the layout is noise and bug free, that is.
best
DaveP
The DC heater supply is finished and tested with the tubes in, everything is ok but I had to reduce the 1 ohm dropper to 0.47 ohms, current is ~2.5A @6.3V The OD3 is a BIG MUTHER.
Power Supply almost finished and all components in place, tight fit but do-able.
Always put in more tags than you need and keep wires long for as long as possible.
All the tubes heaters wired up, separate ground back to cap negatives, no need to use twisted pairs with DC.
The amp should be best part done and fired up next week.
The front panel is going to be the tricky part :-\
Power Supply almost finished and all components in place, tight fit but do-able.
Always put in more tags than you need and keep wires long for as long as possible.
All the tubes heaters wired up, separate ground back to cap negatives, no need to use twisted pairs with DC.
The amp should be best part done and fired up next week.
The front panel is going to be the tricky part :-\
Mike Cleaver
Well-known member
Looking great, Dave!
Nice to see someone doing point to point wiring with a good layout.
Hope she sounds as good as she looks!
Nice to see someone doing point to point wiring with a good layout.
Hope she sounds as good as she looks!
Thanks Mike,
Hope it brought back some memories of the old tube days. The date on the 6V6 tube boxes was 1949, same age as me, only trouble is they are in much better shape!
I'm looking forward to firing up the amp next so that I can check just what the voltages really are, I never did find them on any manual.
Can't say I'm looking forward to wiring up all the switch gear that much, that gets tedious cos you have to be sooo careful not to foul up. I'm quite interested as to how the meter will work though.
best
DaveP
Hope it brought back some memories of the old tube days. The date on the 6V6 tube boxes was 1949, same age as me, only trouble is they are in much better shape!
I'm looking forward to firing up the amp next so that I can check just what the voltages really are, I never did find them on any manual.
Can't say I'm looking forward to wiring up all the switch gear that much, that gets tedious cos you have to be sooo careful not to foul up. I'm quite interested as to how the meter will work though.
best
DaveP
dustbro
Well-known member
very inspiring 
what a clean build! Cant wait to see it in action
what a clean build! Cant wait to see it in action
Hi Doug,
You were able to give me some that you had measured yourself from an original, but not all.
I managed to calculate the rest with some algebra I thought I'd forgotten, so it will be good to see if it all checks out.
When the projects finished I'll post them all on the schematic on the forum.
best
DaveP
You were able to give me some that you had measured yourself from an original, but not all.
I managed to calculate the rest with some algebra I thought I'd forgotten, so it will be good to see if it all checks out.
When the projects finished I'll post them all on the schematic on the forum.
best
DaveP
